Topically applicable anti-inflammatory O/W emulsions comprising pro-penetrating glycols

ABSTRACT

Stable, topically applicable, non-greasy and non-tacky oil-in-water (O/W) anti-inflammatory emulsions, useful, e.g., for the treatment of psoriasis, contain: a. a therapeutically effective amount of at least one steroidal anti-inflammatory agent, notably clobetasol propionate; b. a pro-penetrating system which includes at least one pro-penetrating glycol and at least one other pro-penetrating agent; and  
     c. at least one polymeric emulsifier not sensitive to electrolytes, for example not an acrylate/C 10 -C 30  alkyl acrylate copolymer, formulated into a topically applicable, pharmaceutically acceptable vehicle therefor.

CROSS-REFERENCE TO PRIORITY APPLICATION

This application claims priority under 35 U.S.C. § 119 of FR 06/02283, filed Mar. 15, 2006, hereby expressly incorporated by reference and assigned to the assignee hereof.

CROSS-REFERENCE TO COMPANION APPLICATION

Copending application Ser. No. ______ [Attorney Docket No.1034227-000106], filed concurrently herewith and also assigned to the assignee hereof.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to novel compositions in the form of emulsions of oil-in-water (O/W) type for topical application, comprising a novel combination of pro-penetrating agents including at least one glycol, a suitable emulsifying system and a bioactive agent of the family of steroidal anti-inflammatory agents.

2. Description of Background and/or Related and/or Prior Art

There currently exist many topical compositions comprising a steroidal anti-inflammatory agent and a high content of glycol, the latter promoting the penetration of the steroidal anti-inflammatory agent into the skin. Given the high content of pro-penetrating glycol, these compositions are formulated in the form of emulsions with a high content of fatty phase, which are also commonly known as “lipocreams”, in the form of anhydrous compositions known as “ointments”, in the form of fluid compositions with a high content of volatile solvents, such as ethanol or isopropanol, intended for application to the scalp, also known as “hair lotions”, or in the form of viscous O/W emulsions, which are also known as “O/W creams”.

For example, O/W creams comprising a corticoid and a high percentage of propylene glycol, marketed under the trademark Temovate® by Glaxo, are known. However, the stabilization of a formulation comprising such a percentage of glycol makes it necessary to include in the emulsion emulsifiers and stabilizers of glyceryl stearate or PEG 100 stearate type or, alternatively, stabilizers or consistency factors of white wax or cetostearyl alcohol type, which lead to the formation of a thick cream of waxy appearance.

In its patent application FR 2,753,626, the assignee hereof describes more fluid emulsions containing a corticoid that have a high percentage of propylene glycol. However, since the high percentage of propylene glycol makes it difficult to prepare the emulsion, it would be advantageous to have available a novel stable formulation of O/W emulsion type, containing less propylene glycol, which has a non-greasy and non-tacky aspect, while at the same time maintaining the rheological and pro-penetrating properties of the composition.

SUMMARY OF THE INVENTION

Ths the present invention features novel pharmaceutical compositions in the form of emulsions of oil-in-water (O/W) type for topical application, comprising, formulated into a pharmaceutically acceptable vehicle:

-   a) at least one steroidal anti-inflammatory agent; -   b) a pro-penetrating system which comprises at least one glycol and     at least one additional pro-penetrating agent; and -   c) a polymeric emulsifying system.

DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OF THE INVENTION

Among the steroidal anti-inflammatory agents that are exemplary are hydrocortisone, anthranoids, betamethasone valerate and clobetasol propionate. The steroidal anti-inflammatory agent is preferably clobetasol propionate.

Advantageously, the compositions according to the invention comprise from 0.0001% to 5% by weight and preferably from 0.025% to 1% by weight of an active agent relative to the total weight of the composition.

In one preferred embodiment according to the invention, the composition comprises from 0.025% to 0.5% by weight and preferentially 0.05% by weight of clobetasol propionate relative to the total weight of the composition.

The principal objective of the compositions according to the invention is to reduce the percentage of propylene glycol employed in the prior art by replacing same with a mixture selected so as to obtain the desired pro-penetrating properties without encountering the previous difficulties of emulsification and of stabilization of the emulsion caused by the high percentage of propylene glycol.

Thus, the pro-penetrating system according to the invention comprises at least one glycol and at least one additional pro-penetrating agent.

Exemplary glycols according to the invention are: alkylene or polyalkylene glycols. Non-limiting examples thereof include (C1 to C6) alkylene and polyalkylene glycols, such as ethylene glycol, polyethylene glycol (2 to 20 monomers), propylene glycol, dipropylene glycol, butylene glycol, pentylene glycol and hexylene glycol. These may or may not be oxyethylenated (2 to 50 EO). Also exemplary are glycol ethers, such as ethoxydiglycol or diethylene glycol monoethyl ether, marketed under the trademark Transcutol HP by Gattefosse, propylene glycol laurate marketed under the trademark Lauroglycol by Gattefosse, propylene glycol dicaprate dicaprylate marketed under the trademark Estol 1526 by Uniqema, and propylene glycol dipelargonate.

The glycols that are preferred according to the invention are propylene glycol, dipropylene glycol, propylene glycol dipelargonate, propylene glycol laurate, ethoxydiglycol and propylene glycol dicaprate dicaprylate.

The pro-penetrating system also comprises at least one additional pro-penetrating agent.

The said additional pro-penetrating agent is selected from the glycols listed above and the pro-penetrating agents of the family of fatty esters, fatty acids or fatty alcohols, or alcohols. Non-limiting examples of such pro-penetrating agents according to the invention other than glycols include ethanol, dimethyl isosorbide marketed under the trademark Arlasolve DMI by Uniqema, methylpyrrolidone marketed under the trademark Pharmasolve by ISP, oleic acid marketed under the trademark Oléine V2 by Stéarinerie Dubois, PEG-8 capric/caprylic glycerides, marketed under the trademark Labrasol by Gattefosse, and oleyl alcohol marketed under the trademark HD Eutanol V PH by Cognis.

Preferably, the compositions according to the invention comprise the following combinations of pro-penetrating agents:

-   propylene glycol and dimethyl isosorbide, -   propylene glycol and ethanol, -   propylene glycol, diethylene glycol monoethyl ether and propylene     glycol laurate, -   propylene glycol and methylpyrrolidone, -   propylene glycol, dimethyl isosorbide and ethanol, -   propylene glycol, methylpyrrolidone and oleyl alcohol.

Preferentially, the compositions according to the invention comprise from 20% to 60% by weight and preferably from 35% to 47% by weight of pro-penetrating glycol, relative to the total weight of the composition, and from 0.5% to 40% by weight and preferentially from 1% to 20% by weight of additional pro-penetrating agent, relative to the total weight of the composition.

The compositions according to the invention are emulsions and thus contain a fatty phase and an aqueous phase.

The fatty phase of the emulsions according to the invention may comprise fatty substances usually employed in the intended field of application.

Among these, exemplary are silicone fatty substances such as silicone oils, and also non-silicone fatty substances such as plant, mineral, animal or synthetic oils.

Among the silicone fatty substances, exemplary are:

-   (i) poly(C₁-C₂₀)alkylsiloxanes and especially those containing     trimethylsilyl endgroups, preferably those with a viscosity of less     than 0.06 m²/s, among which representative are linear     polydimethylsiloxanes and alkylmethylpolysiloxanes such as cetyl     dimethicone (CTFA name), -   (ii) volatile silicone oils, such as:     -   cyclic volatile silicones containing from 3 to 8 and preferably         from 4 to 5 silicon atoms. These are preferably         cyclotetradimethylsiloxane, cyclopentadimethylsiloxane or         cyclohexadimethylsiloxane,     -   cyclocopolymers of the dimethylsiloxane/methylalkylsiloxane         category, such as Silicone FZ 3109 marketed by Union Carbide,         which is a dimethylsiloxane/methyloctylsiloxane cyclocopolymer,     -   linear volatile silicones containing from 2 to 9 silicon atoms.         These are, for example, hexamethyldisiloxane,         hexylheptamethyltrisiloxane or octylheptamethyltrisiloxane, -   (iii) phenylsilicone oils, especially those of formula:     in which:     -   R is a C₁-C30 alkyl radical, an aryl radical or an aralkyl         radical,     -   n is an integer from 0 and 100,     -   m is an integer from 0 and 100, with the proviso that the sum         n+m ranges from 1 and 100.

Among the non-silicone fatty substances that are exemplary are common oils, such as liquid paraffin, liquid petroleum jelly, sweet almond oil, perhydrosqualene, apricot oil, wheat germ oil, sweet almond oil, beauty-leaf oil, palm oil, castor oil, avocado oil, jojoba oil, olive oil or cereal germ oil; esters of fatty acids or of fatty alcohols, such as octyidodecyl alcohol or polyalcohol octanoates, decanoates or ricinoleates; fatty acid triglycerides; glycerides; hydrogenated polyisobutene, hydrogenated oils that are solid at 25° C.; lanolins; fatty esters that are solid at 25° C.

These fatty substances may be variously selected, in particular, by one skilled in this art in order to prepare a composition having the desired properties, for example in terms of consistency or texture.

Thus, the fatty phase of the emulsions according to the invention may be present in a content of from 5% to 50% by weight and preferably from 15% to 25% by weight relative to the total weight of the composition.

The aqueous phase of the emulsions according to the invention may comprise water, a floral water such as cornflower water, or a natural spring or mineral water selected, for example, from among l'eau de Vittel, waters from the Vichy basin, l'eau d'Uriage, l'eau de la Roche Posay, l'eau de Bourboule, l'eau d'Enghien-les-Bains, l'eau de Saint Gervais-les-Bains, l'eau de Néris-les-Bains, l'eau d'Allevard-les-Bains, l'eau de Digne, l'eau de Maizières, l'eau de Neyrac-les-Bains, l'eau de Lons-le-Saunier, les Eaux Bonnes, l'eau de Rochefort, l'eau de Saint Christau, l'eau de Fumades, l'eau de Tercis-les-bains, l'eau d'Avène or l'eau d'Aix les Bains.

The said aqueous phase is advantageously present in a content of from 10% to 70% by weight and preferably from 20% to 40% by weight relative to the total weight of the composition.

Advantageously, a stable emulsion according to the invention is obtained by preferably selecting at least one polymeric emulsifier as suitable emulsifying system.

Moreover, the emulsifying system is selected such that the composition according to the invention is physically and chemically stable over time.

According to the invention, the term “physical stability” refers to a composition that does not present any macroscopic change of appearance (phase separation, change in color of appearance, etc.) or microscopic change of appearance (recrystallization of the active agent) after storage at temperatures of 25° C. (=room temperature: RT), 4° C. and 40° C., for 3 months.

According to the invention, the term “chemical stability” refers to a composition in which the content of active principle remains stable after three months at room temperature and at 40° C. A stable content of active principle means according to the invention that the content shows very little variation relative to the initial content, i.e., the variation in the content of active principle at time T should not be less than 90% to more particularly than 95% of the initial content at T0.

The difference between the polymeric emulsions and conventional emulsions is the manner in which the emulsion is created. Polymeric emulsions are stabilized by means of the formation of gel particles that surround the oil droplets. Thus, the oil droplet is immobilized in the gelled network and the emulsion is formed. Polymeric emulsions differ from standard emulsions stabilized with conventional emulsifying agents on account of their irritant potential: by virtue of their high molecular weight, polymeric emulsifiers are not capable of penetrating the stratum corneum.

Polymeric emulsifiers are especially described by Clymans & Brand in “Cosmetics and Toiletries” (published worldwide, 1995, 119-125).

The most conventional polymeric emulsifiers are the Pemulen products obtained by grafting a linear carbon-based chain onto a synthetic polymer of vinyl or acrylic type that is initially totally hydrophilic. However, emulsions prepared with these polymeric emulsifiers have the drawback of being sensitive to electrolytes. Thus, in the present invention, the said crosslinked polymers of Pemulen type, and especially the products marketed by Goodrich under the trademarks Pemulen TR1, Pemulen TR2, Carbopol 1342 or Carbopol 1382, will not be used; these polymers, of acrylate/C10-30 alkyl acrylate crosspolymer type, which are copolymers comprising a major fraction of acrylic acid and a small fraction of C₁₀-C₃₀ (meth)acrylic acid esters, are thus excluded from the present invention.

On the other hand, as polymeric emulsifiers that may be used according to the invention, and which do not have the drawbacks mentioned above, exemplary are:

-   the Sepigel/Simulgel products, the Aristoflex products, which are     mixtures essentially consisting of acrylic polymers combining these     acrylic polymers with a surfactant and/or a lipophilic chain. They     have colloidal, macromolecular surfactant and emulsifying     properties. Also exemplary are Simulgel 600 (mixture of polysorbate     80 and of isohexadecane and of acrylamide/sodium     acryloyldimethyltaurate) and the Sepiplus products marketed by     SEPPIC or the Aristoflex products (hydrophilic acrylic polymers),     and especially Aristoflex AVC (ammonium acryloyldimethyltaurate/VP     copolymer) or Aristoflex HMB marketed by Clariant. Simulgel 600 and     Aristoflex AVC will preferably be used according to the invention. -   cyanoacrylic polymers of Aculyn type, marketed by Rohm & Haas, which     are anionic associative rheology modifiers and which act as     polymeric emulsifiers. These polymers stabilize the emulsion by     trapping the oil drops in a three-dimensional network of polymer     chains, which avoids reagglomeration of the oil drops and     consequently stabilizes the emulsion. This type of amphiphilic     polymer combines hydrophilic and hydrophobic structural units,     which, in aqueous solution, become organized by forming hydrophobic     aggregates similar to surfactant miscelles. These hydrophobic     aggregates thus make it possible to formulate emulsions that are     very stable even without surfactant. Among the emulsifiers that are     preferred according to the invention, Aculyn 22 will be selected.

The compositions according to the invention comprise from 0.1% to 10% by weight, advantageously from 0.5% to 5% by weight and preferably from 0.2% to 3.5% by weight of suitable polymeric emulsifying system, relative to the total weight of the composition.

Moreover, depending on the nature of the emulsifier used, the compositions according to the invention may comprise from 0% to 3% by weight and preferably from 0.1% to 2% by weight, relative to the total weight of the composition, of at least one co-emulsifier, which, by reducing the surface tension of the dispersed phase, will allow adjustment of the droplets of the emulsion. The co-emulsifiers according to the invention include esters of saturated or unsaturated, natural or synthetic fatty acids, especially of oleic acid or (iso)stearic acid, such as the polyglyceryl esters of isostearic acid marketed under the trademark Lameform TGI by Sidobre-Sinnova Henkel, sorbitan isostearate marketed under the trademark Arlacel 987 by Uniqema, sorbitan sesquioleate marketed under the trademark Arlacel 83 by Uniqema, sorbitan laurate marketed under the trademark Span 20 by Uniqema, esters of glycol and of isostearic acid, for instance PEG-6 isostearate marketed under the trademark Olepal Isostearique by Gattefosse, esters of sorbitol and of oleic acid, for instance the polysorbates marketed under the trademark Tween by Uniqema, fatty alcohol ethers, especially of oleyl alcohol, in particular esters of glycol and of oleyl alcohol, for instance the oleth products marketed under the trademark Brij by Uniqema, oxyethylenated sorbitan monostearate, and fatty alcohols such as stearyl alcohol or cetyl alcohol.

Sorbitan esters, especially sorbitan laurate, or polyglycerol esters will preferably be used according to the invention.

Preferentially, the compositions according to the invention will comprise from 0.05% to 5% by weight and even more preferentially from 1% to 2% by weight of sorbitan esters or of polyglycerol esters, relative to the total weight of the composition.

Preferably, according to the invention, the subject compositions comprise, formulated into a pharmaceutically acceptable vehicle:

-   0.0025% to 0.5% of clobetasol propionate, -   30% to 50% of a pro-penetrating glycol, -   1% to 20% of at least one additional pro-penetrating agent, -   0.1% to 5% of at least one polymeric emulsifier, -   0 to 5% of co-emulsifier.

Even more preferentially, the compositions comprise:

-   0.0025% to 0.5% of clobetasol propionate, -   30% to 50% of at least one pro-penetrating glycol selected from     among propylene glycol, diethylene glycol monoethyl ether and     propylene glycol laurate, -   1% to 20% of at least one additional pro-penetrating agent selected     from among diethylene glycol monoethyl ether, propylene glycol     laurate, dimethyl isosorbide, ethanol and methylpyrrolidone, -   0.1% to 5% of at least one polymeric emulsifier selected from among     acrylic polymers and cyanoacrylic polymers, -   0 to 5% of co-emulsifier selected from PEG-6 isostearate,     polyglyceryl-3 diisostearate and sorbitan laurate.

In one particular embodiment according to the invention, it has been found that it is possible to obtain a physically and chemically stable emulsion by using an emulsifier alone without the presence of co-emulsifier or of gelling agent when the emulsifier used is an emulsifier from the Sepigel/Simulgel family.

The pH of the compositions according to the invention advantageously ranges from 5 to 7.5 and preferably from 5.5 to 6.5. It will be adjusted to the desired value by adding conventional mineral or organic acids or bases.

The emulsions may also comprise any additive usually included in cosmetics or pharmaceuticals, such as gelling agents, antioxidants, dyes, fragrances, essential oils, preservatives, cosmetic active agents, moisturizers, vitamins, essential fatty acids, sphingolipids, self-tanning compounds such as DHA, sunscreens, liposoluble and especially hydrocarbon-based polymers, such as polybutene, polyalkylenes, polyacrylates and silicone polymers that are compatible with fatty substances. Of course, one skilled in this art will take care to select this or these optional additional compound(s), and/or the amount thereof, such that the advantageous properties of the compositions according to the invention are not, or are not substantially, adversely affected by the envisaged addition.

These additives are advantageously present in the compositions in a proportion of from 0% to 10% by weight relative to the total weight of the composition.

The present invention also features the administration (whether regime or regimen) of the subject compositions as medicaments for treating psoriasis.

In order to further illustrate the present invention and the advantages thereof, the following specific examples are given, it being understood that same are intended only as illustrative and in nowise limitative. In said examples to follow, all parts and percentages are given by weight, unless otherwise indicated.

EXAMPLE 1

Water qs 100 ammonium acryloyldimethyltaurate/  1.00% VP copolymer clobetasol propionate  0.05% propylene glycol 37.50% dimethyl isosorbide 10.00% liquid paraffin 20.00% PEG-6 isostearate  2.00% sodium hydroxide qs pH 6

Physical and chemical stability of the composition of Example 1: T0 = thick white milk pH = 7.54 Centrifuge: 10 000 rpm: no comments Micro: globule size <2.5 μm T1 month RT Macroscopic Thick white milk, in appearance accordance with T0 pH pH 7.6 Microscopic appearance Globule size 2.5 μm, homogeneous carpet Assay of the active 97.9% agent (HPLC) T0: 99%  4° C. Macroscopic Thick white milk, in appearance accordance with T0 Microscopic appearance Globule size 2.5 μm, homogeneous carpet No recrystallization of the clobetasol Macroscopic Thick white milk, in appearance accordance with T0 40° C. Assay of the active 96.3% agent (HPLC) T0: 99%

EXAMPLE 2

Water qs 100 ammonium acryloyldimethyltaurate/ 1.00% VP copolymer clobetasol propionate 0.05% propylene glycol 42.50%  ethanol 5.00% liquid paraffin 20.00%  PEG-6 isostearate 2.00% sodium hydroxide qs pH 6

T0 = thick white milk pH = 6.7 Centrifuge: 10 000 rpm: no comments Micro: globule size <2.5 μm T1 month RT Macroscopic Thick white milk, in appearance accordance with T0 pH pH 6.7 Microscopic appearance Globule size from 2.5 μm and 7.5 μm, heterogeneous carpet Assay of the active 98.1% agent (HPLC) T0: 99.7%  4° C. Macroscopic Thick white milk, in appearance accordance with T0 Microscopic appearance Globule size from 2.5 μm and 7.5 μm, heterogeneous carpet No recrystallization of the clobetasol 40° C. Macroscopic Thick white milk, in appearance accordance with T0 Assay of the active 97.4% agent (HPLC) T0: 99.7%

EXAMPLE 3

Water qs 100 acrylates/steareth-20 3.50% methacrylate copolymer clobetasol propionate 0.05% propylene glycol 45.00%  diethylene glycol monoethyl ether 1.50% propylene glycol laurate 1.00% liquid paraffin 20.00%  polyglyceryl-3 diisostearate 2.00% sodium hydroxide qs pH 6

T0 = thick white milk pH = 6.33 Centrifuge: 10 000 rpm: slight phase separation Micro: globule size <2.5 μm T1 month RT Macroscopic Thick white milk, in appearance accordance with T0 pH pH 6.36 Microscopic appearance Globule size <2.5 μm, homogeneous carpet Assay of the active 98.3% agent (HPLC) T0: 99.6%  4° C. Macroscopic Thick white milk, in appearance accordance with T0 Microscopic appearance Globule size <2.5 μm, homogeneous carpet No recrystallization of the clobetasol 40° C. Macroscopic Thick white milk, in appearance accordance with T0 Assay of the active 97.6% agent (HPLC) T0: 99.6%

EXAMPLE 4

Water qs 100 acrylamide/sodium acryloyldimethyltaurate 2.00% (and) isohexadecane (and) polysorbate 80 clobetasol propionate 0.05% propylene glycol 46.50%  methylpyrrolidone 1.00% liquid paraffin 20.00% 

T0 = thick white milk pH = 6.51 Centrifuge: 10 000 rpm: no comments Micro: globule size 2.5 to 7.5 μm T1 month RT Macroscopic Thick white milk, in appearance accordance with T0 pH pH 6.47 Microscopic appearance Globule size 7.5 μm to 15 μm, heterogeneous carpet Assay of the active 97.4% agent (HPLC) T0: 101.1%  4° C. Macroscopic Thick white milk, in appearance accordance with T0 Microscopic appearance Globule size 7.5 μm to 15 μm, heterogeneous carpet No recrystallization of the clobetasol Macroscopic Thick white milk, in appearance accordance with T0 40° C. Assay of the active 97.5% agent (HPLC) T0: 101.1%

Each patent, patent application, publication, text and literature article/report cited or indicated herein is hereby expressly incorporated by reference.

While the invention has been described in terms of various specific and preferred embodiments, the skilled artisan will appreciate that various modifications, substitutions, omissions, and changes may be made without departing from the spirit thereof. Accordingly, it is intended that the scope of the present invention be limited solely by the scope of the following claims, including equivalents thereof. 

1. A stable, topically applicable, non-greasy and non-tacky oil-in-water (O/W) anti-inflammatory emulsion, comprising: a. a therapeutically effective amount of at least one steroidal anti-inflammatory agent; b. a pro-penetrating system which comprises at least one pro-penetrating glycol and at least one other pro-penetrating agent; and c. at least one polymeric emulsifier not sensitive to electrolytes, formulated into a topically applicable, pharmaceutically acceptable vehicle therefor.
 2. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said at least one polymeric emulsifier being other than an acrylate/C₁₀-C₃₀ alkyl acrylate copolymer.
 3. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said at least one steroidal anti-inflammatory agent comprising clobetasol propionate.
 4. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said at least one pro-penetrating glycol comprising a C₁ to C₆ alkylene or polyalkylene glycol or a glycol ether and said at least one other pro-penetrating agent comprising a glycol, fatty ester, fatty acid, fatty alcohol or alcohol.
 5. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said at least one pro-penetrating glycol being selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, pentylene glycol, hexylene glycol, propylene glycol dipelargonate, diethylene glycol monoethyl ether, propylene glycol laurate, propylene glycol dicaprate dicaprylate and ethoxydiglycol, and said at least one other pro-penetrating agent being selected from the group consisting of ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, pentylene glycol, hexylene glycol, propylene glycol dipelargonate, diethylene glycol monoethyl ether, propylene glycol laurate, propylene glycol dicaprate dicaprylate, ethoxydiglycol, ethanol, dimethyl isosorbide, methylpyrrolidone, oleic acid, PEG-8 capric/caprylic glycerides and oleyl alcohol.
 6. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said pro-penetrating system comprising a combination of pro-penetrating glycols/agents selected from the group consisting of:
 1. propylene glycol and dimethyl isosorbide,
 2. propylene glycol and ethanol,
 3. propylene glycol, diethylene glycol monoethyl ether and propylene glycol laurate,
 4. propylene glycol and methylpyrrolidone,
 5. propylene glycol, dimethyl isosorbide and ethanol, and
 6. propylene glycol, methylpyrrolidone and oleyl alcohol.
 7. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, further comprising at least one co-emulsifier.
 8. The topically applicable O/W anti-inflammatory emulsion as defined by claim 7, said at least one co-emulsifier being selected from the group consisting of polyglycerol esters of isostearic acid, sorbitan isostearate, sorbitan sesquioleate, sorbitan laurate, glycol esters of isostearic acid, sorbitol esters of oleic acid, glycol esters of oleyl alcohol, oxyethylenated sorbitan monostearate, stearyl alcohol and cetyl alcohol.
 9. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said at least one polymeric emulsifier not sensitive to electrolytes comprising an acrylic and/or cyanoacrylic polymer.
 10. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, comprising: 0.0025% to 0.5% of clobetasol propionate, 30% to 50% of a pro-penetrating glycol, 1% to 20% of at least one other pro-penetrating agent, 0.1% to 5% of at least one polymeric emulsifier, 0 to 5% of co-emulsifier.
 11. The topically applicable O/W anti-inflammatory emulsion as defined by claim 10, comprising: 0.0025% to 0.5% of clobetasol propionate, 30% to 50% of at least one pro-penetrating glycol selected from the group consisting of propylene glycol, diethylene glycol monoethyl ether and propylene glycol laurate, 1% to 20% of at least one other pro-penetrating agent selected from the group consisting of diethylene glycol monoethyl ether, propylene glycol laurate, dimethyl isosorbide, ethanol and methylpyrrolidone, 0.1% to 5% of at least one polymeric emulsifier comprising an acrylic and/or cyanoacrylic polymer, up to 5% of a co-emulsifier selected from the group consisting of PEG-6 isostearate, sorbitan laurate and polyglyceryl-3 diisostearate.
 12. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, said at least one polymeric emulsifier not sensitive to electrolytes comprising acrylamide/sodium acryloyidimethyltaurate in a mixture of polysorbate-80 and isohexadecane.
 13. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, comprising from 35% to 47% by weight of said at least one pro-penetrating glycol.
 14. The topically applicable O/W anti-inflammatory emulsion as defined by claim 13, comprising from 1% to 20% by weight of said at least one other pro-penetrating agent.
 15. The topically applicable O/W anti-inflammatory emulsion as defined by claim 1, having a pH ranging from 5 to 7.5.
 16. The topically applicable O/W anti-inflammatory emulsion as defined by claim 15, having a pH ranging from 5.5 to 6.5.
 17. A regime or regimen for treating psoriasis, which comprises topically applying onto the affected skin area of an individual in need of such treatment, a thus effective amount of a stable, non-greasy and non-tacky oil-in-water (O/W) anti-inflammatory emulsion, comprising: a. a therapeutically effective amount of at least one steroidal anti-inflammatory agent; b. a pro-penetrating system which comprises at least one pro-penetrating glycol and at least one other pro-penetrating agent; and c. at least one polymeric emulsifier not sensitive to electrolytes, formulated into a topically applicable, pharmaceutically acceptable vehicle therefor. 